Application of Flow Cytometry to Saccharomyces cerevisiae Population Analysis

Abstract

This study was focused on the development and the application of a rapid and reliable staining method for the characterisation of Saccharomyces cerevisiae cells. The experiments were carried out during the shaken flask batch cultivation of yeasts on YEPD medium under aerobic conditions at 27 °C. Stained samples were analysed with an epifluorescence microscope or by employing a flow cytometer. Three different fluorescent probes such as propidium iodide (PI), fluorescein diacetate (FDA), and fluorescein isothiocyanate (FITC) were used for staining. PI was used to determine cell viability in a native sample and DNA content in a sample fixed by ethanol. To assess protein distribution in the yeast population the FITC amine-reactive probe was used. Instantaneous cell enzyme activity was measured as the amount of fluorescein liberated from FDA by intracellular esterase activity.